To begin utilizing xGRAIL privileges, see the video below which explains how to convert GRAIL for xGRAIL. (You can also earn xGRAIL from incentivized active yield farms)
As an example, the user converts 100 GRAIL in return he gets 100 xGRAIL
If you plan to convert GRAIL into xGRAIL, it is important to understand that xGRAIL requires a vesting period before you can redeem it for GRAIL
A video tutorial regarding converting GRAIL to xGRAL is available below.

Instructional video

Convert GRAIL to xGRAIL